A blue whale is usually about 80 to 100 feet (24 to 30 meters) long and can weigh 100,000 to 330,000 pounds (50 to 165 tons). NOAA Fisheries lists a maximum of about 110 feet, and the blue whale is the largest animal known to have ever lived.
Weights on this page are in US tons (2,000 pounds) unless marked metric tons. The Latin name is Balaenoptera musculus, and the blue whale species page has the basic profile.
How Big Is a Blue Whale?
Size varies by population. NOAA says blue whales in the North Atlantic and North Pacific reach about 90 feet and weigh over 100,000 pounds, while the Antarctic subspecies is larger. Females are generally larger than males.
NOAA Fisheries gives a top length of about 110 feet and a top weight of about 330,000 pounds (150 metric tons).
Two records are worth knowing, and they come from different animals:
- Heaviest weighed: a female caught in the Southern Ocean on March 20, 1947. She weighed 190 metric tons (418,878 pounds, or about 209 US tons) and was 90 feet 6 inches (27.6 m) long.
- Longest reported: a female landed at South Georgia in 1909, recorded as 107 Norwegian feet, which converts to about 110 feet (33.6 m). Guinness World Records notes that this is an estimate, and the animal was never weighed.
Both records come from whaling-era measurements made on land, so they are hard to double-check today.
How Big Are the Parts of a Blue Whale?
Heart
The first blue whale heart ever preserved came from a 78-foot whale that washed ashore in Newfoundland in 2014. It weighed about 440 pounds (199.5 kg) and measured about 5 feet from the top of the aorta to the bottom of the lowest chamber. Guinness World Records lists it as the largest heart on record. That is well short of the 1,000-pound, car-sized heart often claimed for blue whales, which was an estimate rather than a measurement.
In a 2019 study, researchers attached a heart-rate tag to a blue whale off California. Its heart slowed to about 2 beats per minute at the lowest point of a dive and rose to 25 to 37 beats per minute at the surface. For more on the organ, see blue whale heart size.
Tongue
Guinness World Records lists the blue whale's tongue as the heaviest of any animal, at about 4 metric tons (8,800 pounds). Some sources give a lower figure of around 2.7 metric tons, so treat the exact weight as approximate.
Calves
A newborn blue whale is about 23 feet long and weighs 5,000 to 6,000 pounds, according to The Marine Mammal Center. The calf drinks milk that is 35 to 50 percent fat and can gain more than 200 pounds a day.
Blue Whale Subspecies and Size
NOAA Fisheries lists five recognized subspecies. Four have names:
- Antarctic blue whale (Balaenoptera musculus intermedia), the largest subspecies.
- North Atlantic and North Pacific blue whale (B. m. musculus).
- Pygmy blue whale (B. m. brevicauda), the smallest subspecies, with mature females around 70 feet long.
- Northern Indian Ocean blue whale (B. m. indica).
The fifth is an unnamed group in the southeastern Pacific.
Blue Whale Size Compared to a Human
A 5.5-foot adult would fit into a 90-foot blue whale about 16 times, end to end. In weight, a 200,000-pound blue whale equals roughly 1,100 people at 180 pounds each.
Despite the bulk, blue whales are not slow. NOAA says they usually travel at about 5 miles per hour and can burst past 20 miles per hour for short stretches.
Blue Whale Size Compared to Other Large Whales
| Whale | Length | Weight |
|---|---|---|
| Blue whale | about 80-100 ft, up to about 110 ft | up to about 330,000 lb (165 tons) |
| Fin whale | 75-85 ft | 40-80 tons |
| Sperm whale (male) | up to 52 ft | up to 45 tons |
| Sperm whale (female) | about 40 ft | about 15 tons |
| Humpback whale | up to about 60 ft | up to about 40 tons |
The fin whale is the second-largest whale, according to NOAA, and it still looks small beside a big blue whale. For detailed head-to-head comparisons, see blue whale vs humpback and sperm whale vs blue whale.
Blue Whale Size Compared to Other Animals
An African bush elephant bull stands about 10.5 feet at the shoulder and weighs about 6 metric tons. A 190-metric-ton blue whale would weigh about as much as 30 of them.
The whale shark is the largest fish, but it is much smaller than a blue whale. Most are 18 to 33 feet long, and the largest reported was 61.7 feet. Weights are estimates because whale sharks are hard to weigh. See whale shark vs blue whale.
Blue Whale Size Compared to Megalodon
Megalodon (Otodus megalodon) lived from about 23 million to roughly 3.5 million years ago, so it never met a modern blue whale. Its size is estimated from fossil teeth and a few preserved vertebrae, and the estimates have moved over time.
A 2022 study modeled a 52-foot (16 m) megalodon weighing more than 61 metric tons. A 2025 study argued for a slimmer body and a maximum of about 80 feet (24.3 m) at around 94 tons.
At the 2022 estimate, megalodon is about 60 percent of a 90-foot blue whale's length and half or less of its weight. At the 2025 upper estimate, it is close to a smaller blue whale in length and weight, but still shorter than the biggest. The blue whale vs megalodon article has the full comparison.
Blue Whale Size Compared to a Brontosaurus
Brontosaurus was a long-necked plant eater from the Late Jurassic. Estimates put it at about 72 feet long and roughly 15 to 20 metric tons. A blue whale is longer and several times heavier.
The blue whale is not longer than every dinosaur, though. The giant long-necked Patagotitan is estimated at about 100 to 120 feet and 50 to 70 metric tons. The most generous estimates for Argentinosaurus approach 100 metric tons, but they are uncertain. A large blue whale outweighs nearly all dinosaur estimates.
Blue Whale Compared to a Boat, a Bus and a Cruise Ship
A 100-foot blue whale is about the length of three 30-foot recreational boats parked end to end.
A school bus is about 40 feet long, so a 100-foot blue whale is a little over two and a half bus lengths. A football field, counting only the 300-foot playing area, is about three times as long as a large blue whale.
A large cruise ship like Royal Caribbean's Symphony of the Seas is about 1,184 feet long, nearly 12 times the length of a 100-foot whale. Its listed 228,081 gross tons measure enclosed volume, not weight, so that number cannot be compared directly with a whale's weight.
How Did Blue Whales Get So Big?
Giant baleen whales are a recent development. A 2017 study found that very large baleen whales appeared along several branches of the whale family tree about 2 to 3 million years ago. Researchers linked this to the start of the ice ages, when seasonal pockets of dense prey formed in coastal waters. Large whales could travel to those patches and filter-feed on them efficiently, so bigger bodies paid off.